Hang fire

[Travelor]

I have reloaded 50 rounds of 7.5x55 Swiss with 168 grain Sierra MatchKing bullets,seated .010" off the lands), 43.9 grains of IMR 4064, and Wolf Large Rifle primers, in Pvi Partizan cases. I am getting hangfires in about 20% of the shots. The gun is a K31 Swiss Schmidt-Rubin. QuickLoad indicates the pressures should be in the 43,000 range with a muzzle velocity of 2640 fps.

My first thought was that the pressures is not getting high enough quickly enough to properly burn the powder, but the pressure indications on the primer show good pressures,ie slightly flattened).

Second thought is that it could be a weakened firing pin spring causing erratic ignition.

Any idea what is up?

George

 

[Chuckhunter]

Travelor, I would first try a hotter primer, like a fed. 210 or 215 Mag, WLRM, or Rem 9 1/2 or9 1/2M. If the problem still continues, then I would look at the firing pin spring and if it appears weak, change it. Are you sure the powder hasn't incurred some moisture? I got hang fires with the wolf primers but I was shooting a ball powder, once I changed to a Mag primer, the problem was resolved. IMR4064 shouldn't be a hard powder to ignite, that's why I asked about the powder. If you have a different lot of 4064, you could try that first. Please let us know what you find.

 

[Travelor]

Chuckhunter - Thanks for the help.

Powder is dry. I'll switch primers and try.

George

 

[280man]

Might be the very hard cups of the Wolf primers or firing pin is not hitting hard enough

 

[2506]

Make sure that you seat those Wolf primers good. The anvil sticks up out of the cup a bit and when you seat the primer you need to feel the anvil hit bottom then you need seat a little deeper so you feel the cup hit the bottom of the primer pocket. When I first started using Wolf primers I had a couple of fail to fire even with two snaps on them. I removed the primers and hit them with a hammer and they went BANG. I make sure that I seat them really good and have not had any more problems.

 

[Chuckhunter]

2506 is spot on about making sure that the Wolf primers are bottomed out.

 

[7mmXbolt]

Another thing you might want to consider is your primer seating habits. Case lube and solvents on your hands can tranfer onto the primer and can foul a primer easily. I had this happen to me many many years ago and I wasn't willing to accept the fact that it was me and not the primers I was using. It's hard not to handle primers when reloading so I make sure my hands are washed with soap and water real good before I start. Just something to think about if the problem persist.

7mmXbolt

 

[hoosiergc]

I own and shoot quite a few S-R K31's and 1911's. My standard load for the K31's is an FNM case, WW LRP, 43.7grs IMR4064 and a 150gr Hornady FMJBT,shoots better than Sierra MK's for me).This load will shoot 3/4 moa all day.

The first thing I thought of when reading your post was 'is the bolt going all the way home'. In all of my Swiss rifles, solid manipulation of the bolt is required. Can't limp wrist it when closing the bolt or it will not rotate fully into battery. I have never had this cause a hang fire, but have had it cause 'no fire'.

That said, have you shot factory loaded ammo with success?

 

[expiper]

Reload the ones that did fire ..,they are now fireformed) and see if they function properly....it culd be some sorta mis-match of dies/chamber/etc....there may be a lil headspace problem!!???!!!/....Roger

 

[2506]

I would not sweat too much on the thought of improper sizing etc until you try some different primers. Wolf Primers are known to have some problems sometimes. The seating method problem that I stated in my post on page 1 and there have been reports of just plane bad primers that would not go off at all. Try some CCI or WW primers and see if your mis/hang fire problems go away. Also like i stated in my other post, make sure you really seat the Wolf primers fully.

 

[Travelor]

Thanks for the help.

I will get back to the range this weekend hopefully,some health issues with the wife) and try other primers and see what will happen.

George